The present invention relates to the formation of semiconductor devices. More particularly, the invention relates etching to form phase change memory devices.
In the formation of phase change memory, an alloy, such as an alloy of germanium (Ge), antimony (Sb), and tellurium (Te) (hereinafter GST), is used to form phase change memory elements.
In an example of a phase change memory element, each element is made of GST. The elements may be heated and then cooled by passing a current through the element. A fast cool down may be used to provide an amorphous structure with an amorphous resistance (ra). A slower cool down may be used to provide a more crystalline structure with a crystalline resistance (rc), which is different from the first resistance.